New collapsible menu's Sandbox link is a big < >, suggesting that you are going to write in code. As the sandbox is a starting point for newbies, it should suggest exactly the opposite: that this is the place to start writing. Something suggesting a sketch or a pencil, should be better.
Current Sandbox icon:
- Update sandbox icon in OOUI to the new icon
- Release a new version of OOUI (Changing it here should make it propagate to all Minerva and Vector skins)
- Go to Vector and check your sandbox appears in the personal dropdown menu with the new icon.
- Enable advanced mobile mode in settings and check your sandbox appears in the personal dropdown menu